The Miwestern United States (or Midwest or Middle West) is an informal name for a group of north-central states of the United States of America, usually including Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri, Ohio, Nebraska, North Dakota, South Dakota and Wisconsin. A 2006 Census Bureau estimate put the population at 66,217,736. Both the geographic center of the contiguous U.S. and the population center of the U.S. are in the Midwest. The United States Census Bureau divides this region into the East North Central States (essentially the Great Lakes States); and the West North Central States.